The present invention relates to a new type of cutting tool, including an insert holder for clamping an indexable cutting insert provided with a cavity in a cutting seat in the holder body, so that the cutting insert rests against a base surface, a locking pin, fixed in a bore in the holder and extending up in the bore of the cutting insert, being arranged to ensure a stable location of the cutting insert for clamping the cutting insert against at least one lateral support in the cutting seat.
Many different insert holders of the pin type are known, in which clamping of the cutting insert is provided by means of a pin extending up into a hole in the cutting insert, the lever movement of the pin being provided by the opposite end of the pin cooperating with a pressure generating member placed in the holder. The Swedish Patent 357 316 (corresponding U.S. Pat. No. 3,807,007) shows an example of such an insert holder of the pin type. However, with this type of holder, unfavorable positional changes of the cutting insert during the machining operations in progress have sometimes been noted.
Furthermore, it is previously known from, for instance, the Swedish patent specification 368 786 (corresponding U.S. Pat. No. 3,908,255) a pin holder, where a locking pin, fixed in a bore in the insert holder and extending up in a hole in the cutting insert, is arranged to cooperate with a pressure member placed in the insert holder for clamping the cutting insert against at least one lateral support in the cutting seat. However, this type of holder having a built-in toggle joint for engagement with the insert hole is only thought to work together with the type of cutting inserts having a central through hole extending up through the entire cutting insert. Furthermore, this is a necessity with the solution given in said patent SE-368 786 since there it is assumed that the L-shaped arm cooperating with the cutting insert should also have a side projection which is arrange to be able to push the cutting insert from above, downwards against the shim thereof. This type of holder has, however, the disadvantage that it is necessary that the cutting insert has a central through hole. Characteristic for this type of cutting insert is a major risk of breakage of the cutting insert, especially if they are made of mixed ceramics or pure ceramics, which are cutting materials, which are used more and more. Another disadvantage with this type of insert holder is that as the machining operation progresses, dirt and particles fall down in the central insert hole and gather in the bottom of the cavity, which receives the looking device formed as a toggle joint. Occasionally, even difficulties with releasing the cutting insert during insert changing may occur.
The purpose of the invention is now to provide a new and improved type of tool, which is not impaired by the above-mentioned inconveniences. According to the invention, it is proposed that an insert holder be equipped with a hole, which does not pass through the cutting insert, in which hole a substantially L-shaped support pin is received. At the same time, a bore is formed in the holder in which a pressure member is arranged, e.g., by a threaded connection. The pressure member possesses a recessed waist portion for cooperation with a yoke formed on a leg of the support pin. When the pressure member is rotated, on the one hand, a downward force on one arm of the support pin is generated, which causes the cutting insert to be pressed against the bottom surface of the cutting seat, at the same time as a force is generated by the inclination of the support pin which is directed inward towards the holder body, this brings about the clamping of the cutting insert against the lateral support or lateral supports via the support pin.